Reducing the amount of plastic materials disposed of in landfills is an important environmental consideration. One approach has been to use post-consumer and post-industrial recycled plastic materials in newly produced plastic products. With certain plastic materials this is relatively straightforward. However, the recycling of polystyrene is challenging. Polystyrene is a widely used thermoplastic having a hardness, hydrophobic nature, and chemical composition that renders it essentially non-degradable under normal conditions. The foamed version of polystyrene, often referred to as Styrofoam®, poses a particularly serious problem to marine life and natural ecosystems due to it buoyancy, stability, and durability. Among the environmental problems it causes is that it often turns up as floating debris that is consumed by marine life.
Since polystyrene packaging products do not degrade under normal conditions, polystyrene presents substantial problems as a waste material. Recycling could lead to an alleviation of environmental concerns. Developing a way to utilize post-consumer and post-industrial recycled polystyrene would produce tangible benefits.
US 2014/004267 is directed to a radiation curable composition incorporating an inert resin described as a polystyrene resin with a number average molecular weight of between 100 and 5000 Daltons.
U.S. Pat. No. 4,007,311 is directed to an adhesive made from grafting acrylate monomers onto block copolymers of polystyrene-polybutadiene-polystyrene and polystyrene-polyisoprene-polystyrene. The molecular weight of same are between about 25,000 and 250,000 Daltons, preferably between about 50,000 and 150,000 Daltons.
JP 2003002914 is directed to overprint varnish emulsions containing styrene polymers having a molecular weight between 1500 and 2900 Daltons. The polymers are formulated from cross-linkable monomers and/or cross-linkable oligomers and photo-initiators.